1. Field of the Invention
The present invention relates to an image pickup apparatus comprising a CCD type image sensor. More particularly, the present invention relates to a camera comprising a CCD type image sensor and a tilt adjustment mechanism for the image sensor.
2. Description of the Related Art
In a conventional image pickup apparatus, a CCD type image sensor is adhesively bonded to a CCD sheet metal. The CCD sheet metal with the CCD sensor bonded thereto is then threadedly attached to or adhesively bonded to the rearward end of a taking lens. The conventional image pickup apparatus also comprises a tilt adjustment mechanism for the image sensor which comprises a movable plate for positioning an image sensor, the movable plate being capable of tilting the image sensor about one end of a diagonal line within the effective range of image taking in a direction corresponding to an optical axis, a fixed or stationary plate for holding the movable plate, and adjusting screws for performing the adjustment of the movable plate in horizontal and vertical directions (e.g., see Japanese Patent Laid-Open Application No. HEISEI-8 (1996)-248465 (Pages 4 to 5, FIGS. 1 and 2)).
In the conventional general image pickup apparatus, the CCD image sensor is poor of its own precision. In this respect, the problem has arisen in that the positional precision in a focal plane required as an optical performance (which precision mainly relates to any inclination or misalignment of the CCD image sensor relative to the optical axis) cannot be ensured only by threadedly attaching the CCD sheet metal with the CCD image sensor adhesively bonded thereto to the rearward end of the taking lens. In order to overcome such a problem, it is known to employ a method which uses a jig or the like to correct the inclination or misalignment of the CCD image sensor relative to the optical axis when the CCD image sensor is adhesively bonded to the CCD sheet metal or when the CCD metal plate with the CCD image sensor bonded thereto is assembled into the barrel of the image taking lens. In such procedures process, however, the CCD image sensor must be finely adjusted and positioned after the inclination or misalignment of the CCD image sensor relative to the optical axis is detected. Thus, this method requires a large-scaled facility used to adhesively bond the CCD image sensor to the CCD sheet metal, probably resulting in an increase of the initial investment. When the CCD image sensor is merely adhesively bonded to the CCD sheet metal, furthermore, it is likely to cause a misalignment or damage in the CCD image sensor due to vibration or impact.
The conventional image pickup apparatus may also comprise an image sensor tilt adjustment mechanism which adjusts the tilt or inclination in the CCD image sensor by operating adjusting screws from the side of eyepiece. Such an image-sensor tilt adjustment mechanism may make it difficult or probably impossible to adjust the CCD image sensor when the latter has been mounted in the image pickup apparatus or when a picturing jig has been in the image pickup apparatus.
It is an object of the present invention to realize an image pickup apparatus having an image-sensor tilt adjustment mechanism which can easily and simply adjust the tilt of a CCD image sensor relative to the optical axis in a precise and stable manner.
Another object of the present invention is to provide an image pickup apparatus having an image-sensor tilt adjustment mechanism which can hold a CCD image sensor in a more reliable manner.
A further object of the present invention is to realize a downsized image pickup apparatus and particularly a downsized rearward barrel.